It is mainly used in hollow slab beam of bridge in the pouring process, instead of the originally wooden mold, die die alternative. Compared to traditional rigid mandrel, his simple, because either shoe or a steel mould, mandrel takes a long time to complete, and relatively simple inflatable mandrel, it directly into the air to the specified pressure in a steel cage. First steps to save a lot of time.Pour preparation phase not only can save a lot of time, in the final dismantling of core die can also save a lot of time. A required form removal time. Permanent mold generally need to wait for the concrete set more time than pneumatic mandrels release waiting much longer. Because permanent mold removal needs concrete must take, and inflatable mandrel when drawing, needed to take far less than traditional permanent mold for concrete. Breaking die, die, need a little bit of breaking out from the bridge hollow Board, but just released inflatable mandrel, to drag out time was much shorter than the dismantling of a bit of hard modes.